The present invention relates in general to fireplace structures and, in particular, to direct-vent, gas fireplace structures. More specifically, the present invention relates to a direct-vent fireplace that may be configured in one arrangement for top venting and, in an alternate arrangement, for rear venting. The alternate arrangements are enabled by the combination of an inlet cover plate and outlet elbow. The arrangement of this inlet cover plate and outlet elbow relative to the remainder of the fireplace structure determines whether the fireplace will be a top venting unit or a rear venting unit.
U.S. Pat. No. 6,295,981 issued Oct. 2, 2001 to Beal et al. addresses a problem associated with some direct-vent, gas fireplaces namely, the difficulty in selectively and easily venting combustion gases in either a horizontal or a vertical direction. In the context of the present invention, the horizontal direction would correspond to a rear vent arrangement while the vertical direction would correspond to a top vent arrangement. The '981 patent explains some of the realities of conventional fireplace designs and discusses some of the efforts of other designers (inventors) in the following manner.
Gas fireplaces of conventional design typically utilize a source of combustion air from the room being heated. This lowers the efficiency of the gas fireplace because a portion of the heated air in the room is drawn into the combustion chamber and exhausted up the chimney. It is known to provide separate ducting from the outside ambient environment to the combustion chamber to increase the efficiency of the fireplace. The ducted air provides a source of oxygen for combustion in the combustion chamber and decreases the amount of air from the room being heated which is exhausted up the chimney. Such ducting, however, requires additional materials and labor to install.
It is also known in the art to utilize concentric flue pipes to exhaust combustion products to the outside environment and supply combustion air from the outside environment. Such fireplaces are termed “direct-vent” fireplaces and are disclosed, for example, in U.S. Pat. No. 4,793,322 (Shimek I) and U.S. Pat. No. 4,909,227 (Rieger). A direct-vent fireplace has the advantage of utilizing a common concentric flue pipe assembly to both exhaust combustion products from and supply combustion air to the combustion chamber. Moreover, only a single opening need be cut through an exterior wall of a house to accommodate the concentric flue pipe assembly.
In general, a direct-vent fireplace has a first pipe with a diameter larger than and disposed concentrically around a second pipe. The duct formed by the second pipe is used to convey exhaust products from the combustion chamber to the outside environment. The annular space formed between the first and second pipes defines a fresh air conduit through which combustion air flows from the outside ambient environment into the combustion chamber.
A problem with direct-vent gas fireplaces is that the concentric flue pipe assembly cannot be easily vented in both a horizontal or vertical direction. Shimek I and Rieger disclose direct-vent fireplaces which respectively connect the concentric flue to the rear wall and top wall of the fireplace. A concentric flue attached to the rear wall of the fireplace may be easily extended through an adjacent sidewall of the house. However, if it is desirable to exhaust the concentric flue in a vertical direction, the fireplace must be moved forward a sufficient distance to allow coupling of a right angle concentric pipe elbow. Thus, additional floor space is required to accommodate the projected footprint of the fireplace and concentric flue pipe assembly.
A concentric flue pipe assembly attached to the top of a direct-vent fireplace has a similar problem when it is desired to vent the concentric fluid in a horizontal direction (see, e.g., Rieger at Col. 1, lines 23–32). That is, the fireplace must be moved forward a sufficient distance to allow coupling of a right angle concentric pipe elbow.
Because of two possible installation configurations, i.e., vertical or horizontal venting of the concentric flue pipe assembly, it is necessary with conventional direct-vent fireplaces to provide two totally different configurations. That is, for relatively close placement of the fireplace adjacent the outside wall of the house, it is necessary to provide one configuration allowing attachment of the concentric flue pipe assembly to the back of the fireplace for horizontal venting, and a second configuration allowing attachment of the concentric flue pipe assembly to the top of the fireplace for vertical venting. The necessity to provide two different configurations increases inventory requirements at the factory. Reference can be made, for instance, to U.S. Pat. No. 5,320,086 (Shimek II) regarding the same. Shimek II is directed to a single fireplace construction that could be used in both a vertical venting configuration (i.e., relatively straight upwardly from the fireplace) of a horizontal venting configuration (i.e., relatively straight out from the back of the fireplace).
Moreover, such fireplaces should be equipped with a mechanism or process that enables one type of venting (e.g., vertical), while preventing the other type of venting (e.g., horizontal). This would allow any exhaust matter to escape the fireplace via the selected venting type, while preventing the same from escaping via the non-selected type.
Accordingly, it would be desirable to have a fireplace that overcomes the above disadvantages.
The perceived improvement offered by the '981 patent is to first provide both a top port (40) and a rear port (41). These two ports communicate with an outlet box (44) extending from the combustion chamber (11). Each port includes a bottom panel (48) defining a circular hole (49). Next, according to the '981 patent, an air inlet pipe member (60) and a separate air outlet pipe member (61) are provided. Included as part of outlet pipe member (61) is a plate portion (63) that attaches to the bottom panel (48). Inlet pipe member (60) then is assembled in a concentric manner relative to outlet pipe member (61). Inlet pipe member (60) includes an integral cover plate portion (67) that functions to close off the non-selected port.
The present invention discloses a structural configuration that enables selective fireplace conversion to either horizontal (rear) venting or vertical (top) venting. Rather than using an outlet pipe member with a cumbersome plate portion, the present invention uses two separate cover plates. The fireplace is configured with an inner panel set at approximately 45 degrees relative to the horizontal and vertical directions and defines a vent port that is in direct flow communication with the combustion chamber. One feature of the present invention is the use of an outlet elbow. One of the unexpected benefits of this design is an increase in velocity of the heated gas exiting the combustion chamber. This increase in velocity in turn increases the intake air flow thereby increasing the heat output and flame performance of the fireplace. Moreover, this structure provides the ability to attach the inlet/outlet subassembly in a first orientation or arrangement for vertical venting and in a second orientation or arrangement for horizontal venting, while using the same vent port.
The convenience and simplicity of this structure, according to the present invention, is seen as a novel and unobvious advance in the art.